Quoted from Pinballpatton:
I understand what you are saying. That's about what I have tried to do but if you get it lined up like you described it will not go far enough to the left or right to hit those targets.
When I brought my Midway Space Gun home, it turned out the bakelite wiper board was warped and this made it impossible to align the gun across all of the L-R and Up-Down targets. The previous owner had 'wadded up' some bubble wrap and wedged it on top of the board (where all the wires run) between it and the top mounting plate.
I found out that this was the problem the hard way when I removed the bubble wrap (I thought it might just be trash) and it threw everything out of whack. Turns out it need MORE bubble wrap strategically placed to 'flatten out' the board and allow the stylus to align with all the contact points. Works fine now.
I can send a pic of this if you want. Good luck.